Treatment of acrylonitrile polymers with aromatic sulfonic acid half salts



c 2,726,132 H iatented Dec. 6,1955

No Drawing. pplica'tion-April 29', 1953, Serial N6. 349,951 12 Claims. (Cl. 8 -17) This invention relates tonew dye-receptive polymers and fibers prepared therefrom. More specifically, the

invention relates to methods of converting polymers and fibers of non-dye-receptive polymers into polymers of more geheralpurposeutility. 3

It is well-known that polyacrylonitrile and copolymers of 80 percent or moreof acryloiiitr'ile and up to 20 percent of other monomeric substances have excellent fiber-forming properties. In general, the polymers of the prior art are not dye-receptive unless a substantial portion of a chemically reactive coniono her is p'res ent in polymeric form in the acrylon'i'trile polymer. Usually such chemically reactive cornonomers induce a reduction in the optimum physical properties of the fibers prepared from such polymers.

This invention has for an object the provision of a method for increasing the dye-receptivity andthe moisture absorption of aciylonitrile polymers, which does not involve any sensible sacrifice in properties of the fibers or in their utility in textile applications. A further object of this invention is to provide fibers of novel composition which are fully dye-receptive to acid type dyestuifs and have increased moisture absorption properties. Other objects will appear hereinafter.

In accordance .Withtherinvention described herein, the dye-receptivity of acrylonitrile polymers is improved by treatment of the polymers in the form of a solid with the. half salt of an aromatic sulfonic acid and a compound having the structure: I,

wherein R represents hydrogen or an alkyl radical having from 1 to 4 carbon atoms, inclusive, X represents -NH2 or --OH, and ii represents one of the" integers .2 and 3. As representative examples of compounds falling within the scope of the s'tructur'al' forniula may be ,Inentioned ethylene diamine, Z-aminoethanoI', 2-amino-3-propanol, propanediamine, etc. i

The half acid salts which are used. in accordance with this invention are prepared. by dissolving: aromatic sulfonic acid in the'desired diainino or aminohydm compound or by dissolving both thewaci d anddiarnino or aminohydroxy compound in'a common solvent. Satisfactory yields of the salt are obtained with from 0.1 mole to 2 moles of acid per mole of amine compound depending upon the particular amino compound used. In some instances an excess of amino compound is employed to act as a solvent for the salt. The salts useful in the process of this invention are those having the formula wherein X, R, and n' have thevames defined' above" for the diamino and aminohydroxy cnmp'ouaas; and R represents an aryl or alkylaryl radical." I

The exact chemical nature of the reaction which takes place when ac'rylonit'rile polymers are treated with these half acid salts is not fully understood. It is believed, however, that the increased" dye-receptivity results, from the formation and introduction of reactive imida'ioline or oxazoline groups into the polymer chains.

The treatment is etfected by, contacting the polymer at percent acrylonitrile and} p a temperature of from CI to200 C. with at least i 2% y w g t of thehalf acidsalt. continued until the dye-rec epolymer is subta t a ly. increased-.. Th 92. 9.3301 1 depend po the concentration oflthe salt solution and upon the par ticula'r temperature selected which may be as little as a few-seconds at 200 C. and as long as several hours at 100. C. .The process. is .mostadvantageously.conducted, and the most satisfactory modifications of the properties of the polymer obtain 'dlflwfien. the treatmehtis carr ed out at, temperatures of from C. to 1 "7 0 C. for periods of time ranging .fro r rij.to..15.minutes... Suitable polymers for the practice of this inventionare polyacrylonitrile and copolymers, of at least 80 percent of acrylonitrile and up.to. 20 percent of an olefinic monomer copolyrneriz'abl'e therewithpforexarnple, vinyl acetate, or other vinyl ester of monocarhoxylic acid; styrene or other vinyl substituted aromatic hydrocarbon; alpha methylstyrene, or other isopropenyl substituted aromatic hydrocarbon; vinyl chloride, or other vinyl halide; methyl methacrylate, or other; alkyl esterof methacrylic acid; methyl acrylate, or other alkyl ester of acrylic acid; dimethyl fumarate, or. otherdialkyl ester of fumaric acid; dimethyl maleate, or other. dialkyl ester of maleic aeid; vinylidene chloride;.methacrylonitrile; the vinylpyridines; the various alkyl substituted .vinylpyr'idines; and the corresponding vinyl', isopropenyl; 2111311 and methallyl substituted pyridines, quinolines,.imidazoles, pyrazines, oxazoles, imidazolines, pyrimidines, benzimidazoles, benzoxazoles, benzothiazoles, pyridazine s, pyrazoles, pyrroles, triazines and other compounds containing N-heterocyclic ring structures. Thepreparation of the new dye receptive polymers is conducted by subjecting the nitrile groupsof the polymer to the action of the herein disclosed half acid salts. To render the polymer sufiiciently dye-receptive, it is usually necessary to react from 1 to 20 percentof the nitrile groups and by the reaction to convert them into the functional imidazoline radicals. To efiect the desired,re s'ult a substantial excess of the saltshould preferably be us ed In this manner, th elikelihood of reaction of a sufficient number of nitrile groups is incr e'ased. r I The invention is further illustrated by the renewing examples. v a

i Exanfiple l The half acid' salt of ethyl enediamine Was prepared by aldingvlzq, 9 %lf EaGi t .90.' fi:.e y

enedianiine. was used to treat fibers in the following experiments- H Examplell i A star of en, pliepa'rdrraal acolsai aga ajf 97 a viny a t e s mm s i t Pa ,d i zli ample lien- 0 utes at 100 C. A deep red shade was dey oped when the treated skein was washedand then dyed with'.Wool

Fast Scarlet G Supra.

tam Hi i I l A s e and. a r e i i ea an .91 i re n es vn'it i e etj re e txinyj ae e a treated as in Example II for 10 minutes at IASf C. he. m difie fibe s. S X ?..efiet fid,With...W Fast Scarlet, and completely exhausted the dyebath.

Eiizih l Il A skein of fiber, prepared f'roin a eopolyrner of 0"?- percent acrylonitrile and percent yinyl acetate, was treated as in Exa'm 'ale II for 10 minutes at C. The

modified fibers' exhausted a we Fast Scarlet dyebath in one minute at room temperature. i

. Enukblv I Ase'ries 6f polyacrylonitrile fiber skein s 'was 'treated The treatment is.

as in Example II under the following conditions and with the following results when dyed with Wool Fast Scarlet.

Conditions of Treatment Results Time ag Dyeabillty None (Control) Very Poor. 2 min 155 Poor. 5 min 155 Good. min 155 Excellent. 10 min- 135 Do. 10 min 120 Fair. 30 min 120 Good.

Example VI One gram of benzene sulfonic acid was dissolved in 50 g. of ethylenediamine. A skein of polyacrylonitrile fiber was added to the resulting salt and the solution refluxed at 170 C. for 30 minutes. The skein was then washed and dyed readily with Wool Fast Scarlet.

Example VII Seventy grams of benzene sulfonic acid was dissolved in 24 g. of ethylenediamine. A skein of polyacrylonitrile fiber was treated in the resulting salt for 10 minutes at 155 C. The washed fibers dyed readily to a deep red shade with Wool Fast Scarlet.

- Example VIII Forty grams of benzene sulfonic acid was dissolved in 30 g. of Z-aminoethanol and heated to 155 C. A skein of polyacrylonitrile fiber was treated with the resulting salt for 10 minutes at that temperature and then washed. The treated skein dyed readily with Wool Fast Scarlet.

The examples illustrate improved dye-receptivity with a specific acid dyestuff. Similar improved affinity is obtained toward other acid dyestuffs, e. g., neutral dyeing colors, sour dyeing colors, anthraquinone dyes, and premetalized azo dyes.

While the process of this invention has been illustrated with reference to treatment of fibers, it is also applicable to the treatment of other solid forms of acrylonitrile polymers. It is necessary that the polymer to be treated be in solid form, however, as the process is not applicable to the treatment of solutions of polymers.

The process of this invention is simple and economical and through its use the markedly improved dye-receptivity of acrylonitrile fibers is obtained without sacrifice in essential fiber properties, such as elongation and tensile strength. Fibers composed of acrylonitrile polymers treated in accordance with the process described herein can be dyed directly with acid dyestuffs. In addition, fibers so treated show a great increase in moisture absorption properties.

It will be understood to those skilled in the art that I many apparently widely different embodiments of this invention can be made without departing from the scope and spirit thereof. Accordingly, it is to be understood that this invention is not limited to the specific embodiwherein X represents one of the group consisting of NH2 and -OH, R represents one of the group consisting of hydrogen and alkyl radicals having from 1 to 4 carbon atoms. inclusive, R represents a radical sewherein X represents one of the group consisting of ,-NH2 and OH, R represents one of the group consisting of hydrogen and alkyl radicals having from 1 to 4 carbon atoms, inclusive, R represents a radical selected from the group consisting of aryl and alkylaryl radicals, and n represents one of the integers 2 and 3, at a temperature of from 100 C. to 200 C. until the dye-receptivity of the said polymer is substantially increased.

3. The process set forth in claim 1 in which the compound is the half salt of an aromatic sulfonic acid and 2-amino-3-propanol.

4. The process set forth in claim 1 in which the compound is the half salt of an aromatic sulfonic acid and ethylenediamine.

5. The process set forth in claim 1 in which the compound is the half salt of an aromatic sulfonic acid and 2-aminoethanol.

6. The process set forth in claim 1 in which the compound is the half salt of aromatic sulfonic acid and propanediamine.

7. A process for dyeing solid polymers of at least percent acrylonitrile which comprises subjecting said polymer to the action of at least 2 percent based on the weight of said polymer, of a compound having the forwherein X represents one of the group consisting of --NH2 and -OH, R represents one of the group consisting of hydrogen and alkyl radicals having from 1 to 4 carbon atoms, inclusive, R represents a radical selected from the group consisting of aryl and alkylaryl radicals, and n represents one of the integers 2 and 3 at a temperature of from C. to 200 C. until the dyereceptivity of the polymer is substantially increased, and subsequently dyeing the polymer with an acid dyestuif.

8. The process of claim 7 in which the polymer is in the form of a filament.

9. The process of claim 7 in which the compound is added to the dye bath.

10. A dye-receptive acrylonitrile polymer which is the reaction product obtained by reacting polymeric acrylonitrile with a compound having the formula:

wherein X represents a member of the group consisting of 'NHz and OH, R represents a member of the group consisting of hydrogen and alkyl radicals having from 1 to 4 carbon atoms, inclusive, R represents a radical selected from the group consisting of aryl and alkylaryl radicals, and n represents an integer from 2 to 3, inclusive, at a temperature of from 100 C. to 200 C. until the dye-receptivity of the polymeric acrylonitrile is substantially increased.

11. The composition of claim 10 wherein the compound is the half salt of an aromatic sulfonic acid and ethylenediamine.

12. The composition of claim 10 wherein the compound is the half salt of an aromatic sulfonic acid and Z-aminoethanol.

No references cited. 

1. A PROCESS WHICH COMPRISES CONTACTING A SOLID POLYMER OF AT LEAST 80 PERCENT ACRYLONITRILE WITH AT LEAST 2 PERCENT, BASED ON THE WEIGHT OF SAID POLYMER, OF A COMPOUND HAVING THE FORMULA: 